Tetracyclines Quinapril

ACE INHIBITORS TETRACYCLINES 1 plasma concentrations and efficacy of tetracyclines with quinapril. The absorption of tetracyclines may be reduced when taken concurrently with quinapril, due to the presence of magnesium carbonate as an excipient in quinapril s pharmaceutical formulation Magnesium carbonate (found in a formulation of quinapril) chelates with tetracyclines in the gut to form a less soluble substance that 1 absorption of tetracycline For short-term antibiotic use, consider stopping quinapril for duration of the course. For longterm use, consider an alternative ACE inhibitor... 

Quinapril Decreased absorption of tetracycline (may result from high magnesium content of quinapril tablets)... 

The absorption of oral tetracycline is reduced by the magnesium carbonate excipient in some quinapril formulations. 

Quinapril, formulated as Accupro also contains magnesium carbonate (250 mg in a 40 mg quinapril capsule, 47 mg in a 5 mg capsule). A pharmacokinetic study in 12 healthy subjects investigating the potential interaction between the magnesium carbonate in these capsules and tetracycline found that single doses of both of these formulations of quinapril markedly reduced the tetracycline absorption. The 5 mg and 40 mg quinapril capsules reduced the tetracycline AUC by 28% and 37%, respectively, and the maximum serum levels were reduced by 25% and 34%, respectively. ... 

An established interaction but the extent of the reduction is only moderate and its clinical importance is uncertain. However, the authors of the study recommend thatthe concurrent use of this formulation of quinapril and tetracycline should he avoided. This is repeated by the manufacturers. Oth-... 

Parke Davis Ltd Effect of magnesium-containing quinapril tablets on the single-dose pharmacokinetics of tetracycline in healthy volunteers, protocol 906-237. Data on file. Report RR 764-00872. 

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